You can do a number of things with the Mac before you hand it back, but if you want to do it properly you will need to put in a little work to preserve your personal data's security, and that's presuming there is no tech support available at your workplace to do it for you.
Apple recommends What to do before you sell, give away or trade in your Mac which is to erase the drive and reinstall macOS. This is the standard practice I've encountered in the workforce regardless of the operating system.
Obviously before this you will need to preserve any files for the next user on a device such as an external drive or office network space, which your company ought to provide. If it's work-related it's the responsibility of the workplace I should have thought.
If that is too onerous you could instead move the work files to a shared folder (AND have a backup) then delete your user account.